Automatic injection device

ABSTRACT

The present invention relates to improvements on automatic injection devices, in particular for self-administered drug therapies, providing for a high degree of internal stability of the syringe and, therefore, of the associated needle, thanks to a series of elastic wasp-waisted elements and a mobile tip made of a transparent material in the preferred embodiment, which besides enabling the regulation of the length of projection of the needle during the injection also allows the user to see the exact spot where the needle will enter the flesh.

BACKGROUND OF THE INVENTION

This invention relates to an automatic injection device, in particularfor andrological use.

Automatic injection devices for self-administered drug therapies arecurrently known, especially for the treatment of erection disorders,where injection devices similar to pens are used to enable patients toself-inject vasoactive drugs directly into the cavernosum, in anextremely safe and simple manner.

Injection devices of the above mentioned type are the subject ofprevious patents and patent applications. The automatic injection deviceof U.S. Pat. No. 4,316,463 by William L. Schmitz comprises a barrelinside which there is a charged ampoule associated with a plunger and aneedle. When the plunger is depressed the ampoule thrusts forward on theneedle, which simultaneously projects from the barrel.

A similar technique is employed in the German model G 8333 718.0.

The automatic injection device of European patent 92304953.0 by OwenMunford Ltd employs a spring loaded drive member which thrusts forwardon a charged capsule and a needle associated with the capsule, theneedle projects from the device injects the drug and immediately afterreturns to the retracted position inside the device.

The injection device of European patent 87116619.5 by Wilhelm HaselmeierGmbH comprises a barrel housing a charged syringe, whose plunger isthrust forward by a piston depressed by a cylindrical body.

The injection device of Italian patent application RM92 A 000881 employsa spring loaded drive member which thrusts forward on the plunger of acharged syringe housed inside the device and ejects the drug through theneedle.

The above mentioned injection devices feature several commoncharacteristics, such as the barrel housing, a generally spring loadedinternal mechanism, which, when activated, thrusts forward on theplunger of a charged syringe or capsule. Unfortunately, these injectiondevices also feature shortcomings which may be especially uncomfortablefor the patient, such as an excessive bulkiness, especially with regardto the length; the impossibility to regulate the force of the springloaded drive member which, when released, thrusts forward on the syringeplunger and the needle; the impossibility to regulate the length of theneedle projecting from the device; the stability of the needle, which isnot always guaranteed; and, last but not least, the excessive bulkinessof the injection devices which are currently available, to the detrimentof what should be one of the key advantages of these devices:discretion.

SUMMARY OF THE INVENTION

According to the present invention there is provided an injection devicecomprising a barrel divided into two sections, the rear section is about⅔ of the total length of the device, while the forward section is ⅓ ofits length; the rear section houses the spring loaded drive member, acatch for holding the forward spring energized, a release mechanism forallowing said member to be sprung forwardly within the barrel, a plungerfor ejecting the charge through the needle and devices for regulatingthe extension of the spring; the forward section of the injection devicecomprises a charged capsule housed inside a sleeve, the needle with acap and the relative spring enabling the extraction of the needle andits return to the needle retracted position, after the removal of theneedle cap; the button for removing the needle cap before using thesyringe; the device for regulating the required needle length during theinjection.

As mentioned above, one of the aims of the present invention is toreduce the bulkiness, and in particular the length, of the injectiondevice when it is not in use, so that it may be carried inside a pocketwith the utmost discretion. Therefore, the spring loaded drive member,the release mechanism and the spring extension regulating device, housedin the rear section, have been designed so as to occupy only a smallpart of this section, thus leaving sufficient room for introducing theforward section of the device, after it has been unscrewed and turnedaround, so as to considerably reduce the length of the injection devicewhen it is not in use. The rear end of the forward section, containingthe empty syringe, is closed by a jointed cylindrical cap.

As mentioned above, the spring loaded drive member which thrusts forwardon the syringe plunger is housed in the rear section of the injectiondevice, inside a cylindrical container co-axial with the barrel, at therear end of which there is a housing for the syringe plunger head; thestroke of the cylindrical container may be regulated in three or morepositions, by means of a pin running inside a toothed selector, thusmaking it possible to regulate the force by which the syringe plunger isthrust forward by the spring loaded drive member.

To regulate the needle projection length during the injection, theforward end of the injection device is provided with an adjustablemobile section, whose length may be increased or reduced, with regard tothe barrel, to allow a shorter or longer portion of the needle,respectively, to project; in the preferred embodiment of the presentinvention the forward end of the infection device is made of atransparent material.

Obviously, an extremely important aspect enabling the correct working ofthe device is the stability of the syringe within the device, to keepthe associated needle always in the correct position; to achieve thisaim, the syringe housed in the rear end of the forward section of thedevice is held firmly in place, by a sleeve, co-axial with the barrel,substantially composed of a series of wasp-waisted elastic elements,which may adapt to the size of the syringe.

For a better understanding of the invention, the preferred embodimentwill now be described in detail, with reference to the accompanyingdrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the injection device when ready for use.

FIGS. 2-4 show the injection device in progressive stages of operation,from ready for use to closed.

FIGS. 5 and 6 show the mechanism for regulating the length of the springloaded drive member, from the inside and the outside, respectively, inthe maximum length position.

FIGS. 7 and 8 show the mechanism for regulating the length of the springloaded drive member, from the inside and the outside, respectively, inthe minimum length position.

FIGS. 9-12 show the stages of assembly of the syringe in the forwardsection of the injection device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the present injection device comprises abarrel divided into two sections, a rear section 1 and a forward section2; the rear section 1 houses the spring loaded drive member 3 containedinside the cylinder 4, co-axial within the barrel 1, which at theforward end is integral with the annulus 5, into one side of which isintroduced the head of the syringe plunger, while on the other sidethere is the catch 6 holding the forward spring energized; at the rearend of the rear section 1 there is the coupling and release mechanism,to which corresponds on the outside the release button; as mentionedabove, when the spring is loaded, the assembly comprising the springloaded drive member 3, the annulus 5 and the catch 6, occupy anextremely reduced space, therefore, the forward end of the rear section1 is practically empty and capable of holding the forward section 2,which must be introduced forward end first; the syringe 7, housed insidethe forward section 2, remains in its place and is protected by the cap8, which is locked in the closed position by the clip 9 running insidethe toothed selector 10.

To prepare the injection device for use, the forward section 2 isextracted from the rear section 1, the syringe is charged with the drugand screwed onto the rear section 1.

In the forward section 2, inside the sliding sleeve 12, there is awasp-waisted elastic element for holding the syringe 7 firmly in place,even during the injection, and enabling the use of syringes of differentsizes.

The sliding sleeve 12 also allows the removal of the cap 13 forprotecting the needle before the injection: a spring 14 enables thesleeve to return to its home position when the control 15 is released.

The tip 16 at the forward end of the forward section 2 is adjustable, byknown means such as a screw mechanism, so as to allow the regulation ofthe length of the projecting needle when in use; this characteristicmakes it possible to better adapt the injection device to its variousrequirements. The tip 16 may be made of a transparent material, thusenabling the patient to view the exact point where the needle will enterthe flesh.

FIGS. 5 to 8 alternately show a full view and a longitudinal section ofthe rear section 1 of the injection device and FIGS. 6 and 8, inparticular, show the device 17 enabling the regulation of the extensionof the spring loaded drive member 3 and, therefore, of the force bywhich the annulus 5 thrusts forward on the syringe plunger when themember is released; as mentioned above, the member 3 is housed inside aninternal cylinder 4 co-axial within the barrel and capable of sliding;the device 17 for regulating the extension of the spring loaded drivemember 3 makes it possible to limit, for example, by means of a pin 18passing between the outer barrel 1 and the inner barrel 4, which may befixed in one of various positions so that, in the case shown in FIG. 6,the stroke of the inner barrel 4, fixed by means of the pin 18 in anintermediate position compared to the outer barrel 1, is longer than thestroke shown in FIG. 8, where the inner barrel 4 is fixed so as to touchthe rear end of the outer barrel 1.

Obviously, different solutions may be adopted, rather than pins engagingin holes, for fixing the position of the inner barrel 4 compared to theouter barrel 1.

What is claimed is:
 1. An automatic injection device comprising: anouter barrel divided into a rear section and a forward section, each ofsaid rear and forward sections comprising a rear end and a forward endwhereby in a use configuration of the injection device the rear end ofsaid forward section is removably screwed to the forward end of saidrear section, and each of said rear and forward sections being hollow,and said forward section has an outside dimension which is smaller thanan inside dimension of said rear section; a syringe housed in saidforward section such that a needle of said syringe is arranged adjacentthe forward end of said forward section and a plunger of said syringe isarranged adjacent the rear end of said forward section; a spring loadeddrive member comprising an annulus for engaging the plunger of saidsyringe in said use configuration and a catch for locking the drivemember in an energized condition, said spring loaded drive member beinghoused in said rear section such that in said energized condition aspring element of said spring loaded drive member is energized andarranged substantially entirely adjacent the rear end of said rearsection and such that said annulus of said spring loaded drive member isarranged adjacent the rear end of said rear section thereby to providean empty space inside said rear section sufficient to allow said forwardsection to be unscrewed from said rear section and to be accommodated,in a non-use configuration of the injection device, inside said emptyspace with the forward end of said forward section arranged adjacent therear end of said rear section; a cap for covering the rear end of saidforward section in said non-use configuration of the injection device,said cap being provided with a catch for releasably attaching said capto said rear section in said non-use configuration of the injectiondevice to hold said forward section inside said rear section thereby fordiminishing the bulk of the injection device in said non-useconfiguration with respect to said use configuration of the injectiondevice; a cylinder slidably accommodated inside said rear section andhaving said annulus of said spring loaded drive member attached to anend of said cylinder for housing said spring loaded drive member in saidrear section; and a pin selectively engageable in one of a plurality ofholes provided in said cylinder and said rear section for selectivelypositioning said annulus in a selected position with respect to theforward end of said rear section for varying the stroke and thrust ofsaid plunger of said syringe provided by said annulus of said springloaded drive member in said use configuration of the injection device.2. The injection device according to claim 1, further comprising asliding sleeve for housing said syringe inside said forward section,said sliding sleeve being provided with an elastic sleeve element forselectively holding syringes of various sizes.
 3. The injection deviceaccording to claim 1, wherein said rear section is longer than saidforward section.
 4. An automatic injection device comprising: an outerbarrel divided into a rear section and a forward section, each of saidrear and forward sections comprising a rear end and a forward endwhereby in a use configuration of the injection device the rear end ofsaid forward section is removably attached to the forward end of saidrear section; a syringe housed in said forward section such that aneedle of said syringe is arranged adjacent the forward end of saidforward section and a plunger of said syringe is arranged adjacent therear end of said forward section; a spring loaded drive member forengaging the plunger of said syringe in said use configuration; and asliding sleeve for housing said syringe inside said forward section,said sliding sleeve being biased by a spring element in a home positiontowards said rear end of said forward section, and said sliding sleevehaving a control element operable by a user to slide said sliding sleeveaway from said home position towards said forward end of said forwardsection whereby said spring element causes said sliding sleeve to returnto said home position upon release of said control element.
 5. Theinjection device according to claim 4, further comprising an adjustabletip which is connected to the forward end of said forward section in anadjustable position for selecting the length of projection of the needleof said syringe with respect to the bottom of said adjustable tip. 6.The injection device according to claim 5 wherein said adjustable tip ismade of a transparent material for viewing the needle of said syringe.7. An automatic injection device according to claim 6, said sidingsleeve being provided with an elastic sleeve element for selectivelyholding syringes of various sizes.
 8. An automatic injection devicecomprising: an outer barrel divided into a rear section and a forwardsection, each of said rear and forward sections comprising a rear endand a forward end whereby in a use configuration of the injection devicethe rear end of said forward section is removably attached to theforward end of said rear section, and each of said rear and forwardsections being hollow, and said forward section has an outside dimensionwhich is smaller than an inside dimension of said rear section; asyringe housed in said forward section such that a needle of saidsyringe is arranged adjacent the forward end of said forward section anda plunger of said syringe is arranged adjacent the rear end of saidforward section; a spring loaded drive member comprising an annulus forengaging the plunger of said syringe in said use configuration and acatch for locking the drive member in an energized condition, saidspring loaded drive member being housed in said rear section such thatin said energized condition a spring element of said spring loaded drivemember is energized and arranged substantially entirely adjacent therear end of said rear section and such that said annulus of said springloaded drive member is arranged adjacent the rear end of said rearsection thereby to provide an empty space inside said rear sectionsufficient to allow said forward section to be removed from said rearsection and to be accommodated, in a non-use configuration of theinjection device, inside said empty space with the forward end of saidforward section arranged adjacent the rear end of said rear section; acylinder slidably accommodated inside said rear section and having saidannulus of said spring loaded drive member attached to an end of saidcylinder for housing said spring loaded drive member in said rearsection; a pin selectively engageable in one of a plurality of holesprovided in said cylinder and said rear section for selectivelypositioning said annulus in a selected position with respect to theforward end of said rear section for varying the stroke and thrust ofsaid plunger of said syringe provided by said annulus of said springloaded drive member in said use configuration of the injection device;and an adjustable tip which is connected to the forward end of saidforward section in an adjustable position for selecting the length ofprojection of the needle of said syringe with respect to the bottom ofsaid adjustable tip.
 9. The injection device according to claim 8wherein said adjustable tip is made of a transparent material forviewing the needle of said syringe.
 10. The injection device accordingto claim 8, further comprising a cap for covering the rear end of saidforward section in said non-use configuration of the injection device,said cap being provided with a catch for releasably attaching said capto said rear section in said non-use configuration of the injectiondevice to hold said forward section inside said rear section thereby fordiminishing the bulk of the injection device in said non-useconfiguration with respect to said use configuration of the injectiondevice.